Electricity consumption at home, what is your consumption?

They are more like witnesses of fresh air. Or moldphobes. Or comfort connoisseurs.

So at least you got us thinking. Since we are forgoing cooling via underfloor heating (€3,800), we are considering installing a controlled residential ventilation system. At around €12k - 35% funding, it's not a big additional effort.

Then do it properly and plan an air well. This will preheat the air in winter and cool it in summer.

The CO2 price was increased by the Bundestag yesterday from 10 to 25€ per ton starting in 2021.

To my knowledge, a CO2 price is now being levied for the first time. But instead of starting the pricing at 10€, it will be directly 25€, contrary to the original decision of the grand coalition. However, this has been certain since 2019. For a house with gas, this means 0.6 cents more per kWh. Depending on the current working price, this amounts to 10-15% additional costs. And this is just the beginning. In 5 years, no one will install a gas heating system in new buildings if this path continues.

Every time I am somewhere in a newly built house, you immediately notice when entering whether the house has ventilation or if the residents ventilate manually enough or not.

To get ahead of that: this cannot be prevented either by "breathable" building materials.

Well, at least you made us think. Since we are forgoing cooling via underfloor heating (3,800 €), we are considering installing a controlled residential ventilation system. At around 12k€ - 35% subsidies, this is not a big additional expense.

Even though I myself am a fan of the central system, which is in the mentioned price range, it does not necessarily have to be the "premium class." Much cheaper options are possible with window rebate ventilators and a few exhaust units. That would be the absolute minimum requirement for me. Beyond that, there are decentralized devices with heat recovery.

Everyone I know with decentralized devices always has them turned off. Thus, a waste of money. Nothing or centralized.

There had occasionally been builders who complained about the sound transmission of the houses in connection with decentralized ventilation. Others like are satisfied with window rebate ventilation and decentralized ventilation in the bathroom. My opinion on controlled residential ventilation: all or nothing

Then do it properly and plan an air well. This will preheat the air in winter and cool it in summer.

There is something about that, namely a controlled residential ventilation with heat recovery is supposed to work best without additional EWT or air wells. There is an Austrian forum, and in the red forum Leitwolf is active who has dealt with this extensively.